Source : Webster's Revised Unabridged Dictionary (1913)

Eel \Eel\, n. [AS. ?l; akin to D., G., & Dan. aal, Icel. [=a]ll,
   Sw. [*a]l.] (Zo["o]l.)
   An elongated fish of many genera and species. The common eels
   of Europe and America belong to the genus {Anguilla}. The
   electrical eel is a species of {Gymnotus}. The so called
   {vinegar eel} is a minute nematode worm. See {Conger eel},
   {Electric eel}, and {Gymnotus}.

Source : WordNet®

eel
     n 1: the fatty flesh of eel; an elongate fish found in fresh
          water in Europe and America; large eels are usually
          smoked or pickled
     2: voracious snakelike marine or freshwater fishes with smooth
        slimy usually scaleless skin and having a continuous
        vertical fin but no ventral fins